This invention relates to a process for preparing .beta.-lactam antibiotics. In particular, it relates to a process for preparing 7.beta.-acylamino (or 7.beta.-protected amino)-3-H cephalosporins and the corresponding 1-carba(dethia)cephalosporins.
Hamashima, in European Patent Application No. 84111916.7, teaches that 3-hydrogen cephalosporins are useful as antibacterial agents in treating infectious diseases in man and animals. Further, among the newer .beta.-lactam antibiotics currently under evaluation are the 1-carba(1-dethia)-3-cephem-4-carboxylic acids. Preparation of these compounds in particular provide considerable synthetic challenges. Among the approaches for synthesis of 1-carba(1-dethia)cephalosporins is the asymmetric process described by Evans, et al., U.S. Pat. No. 4,665,171. Because of the importance of the continued development of .beta.-lactam antibiotics for the treatment of infectious disease, processes for the preparation of such antibiotics are of considerable importance.